This invention relates generally to transparencies, and more specifically the present invention is directed to humidity resistant transparencies comprised of coatings with additives, and the use of these transparencies in ink jet printing processes. In one embodiment, the present invention relates to transparencies comprised of a supporting substrate with certain coatings thereover containing small molecules such as plasticizers and optional fillers as illustrated herein, which transparencies are particularly useful in ink jet printing processes. Additionally, in another embodiment of the present invention there are provided papers for ink jet printing, which papers contain thereover coatings containing small molecules such as plasticizers as illustrated herein with, for example, colloidal silica dispersed therein in, for example, an effective amount, such as from about 30 to about 75 percent by weight. Additionally, in another embodiment of the present invention there are provided plastic papers for ink jet printing, which papers contain thereover coatings containing small molecules such as plasticizers as illustrated herein with, for example, metal oxides such as titanium dioxide dispersed therein, for example, in an effective amount such as from about 10 to about 45 percent by weight. The coated paper substrates of the present invention may also be incorporated into electrostatographic imaging processes.
Ink jet printing systems are well known. Thus, for example, there is described in U.S. Pat. No. 3,846,141 a composition for ink jet printing comprised of an aqueous solution of a water soluble dye and a humectant material formed of a mixture of a lower alkoxy triglycol, and at least one other compound selected from the group consisting of a polyethylene glycol, a lower alkyl ether of diethylene glycol, and glycerol. According to the disclosure of this patent, the viscosity of the printing inks is subjected to little variation with use in that water is lost by evaporation during recirculation of the ink composition through the ink jet printer. Moreover, apparently the humectant system disclosed in this patent substantially prevents or minimizes tip drying of the printing ink in the orifice or nozzle during down time of the printer such as when the printer is rendered inoperative. As further disclosed in the patent, the basic imaging technique in jet printing involves the use of one or more ink jet assemblies connected to a pressurized source of ink. Each individual ink jet includes a very small orifice usually of a diameter of 0.0024 inch, which is energized by magneto restrictive piezoelectric means for the purpose of emitting a continous stream of uniform droplets of ink at a rate of 33 to 75 kilohertz. This stream of droplets is desirably directed onto the surface of a moving web of, for example, paper and is controlled to form printed characters in response to video signals derived from an electronic character generator and in response to an electrostatic deflection system. The disclosure of the '141 patent, especially with regard to the ink jet printing process, is totally incorporated herein by reference.
Also, there are disclosed in U.S. Pat. No. 4,279,653 ink jet compositions containing water soluble wetting agents, a water soluble dye and an oxygen absorber. Similarly, U.S. Pat. No. 4,196,007 describes an ink jet printing composition containing an aqueous solution of water soluble dye and a humectant consisting of at least one water soluble unsaturated compound. Other documents disclosing aqueous inks for ink jet printing include U.S. Pat. Nos. 4,101,329; 4,290,072 and 4,299,630.
Ink jet recording methods and ink jet transparencies using the above-mentioned or similar inks are well known. There is disclosed in U.S. Pat. No. 4,446,174 an ink jet recording method for producing a recorded image on an image receiving sheet with aqueous inks, and wherein an ink jet is projected onto an image receiving sheet comprising a surface layer containing a pigment, which surface layer is capable of adsorbing a coloring component present in the aqueous ink. Also, there is disclosed in U.S. Pat. No. 4,371,582 an ink jet recording sheet containing a latex polymer, which can provide images having excellent water resistance properties and high image density by jetting them onto an aqueous ink containing a water soluble dye. Similarly, U.S. Pat. No. 4,547,405 describes an ink jet recording sheet comprising a transparent support with a layer comprising 5 to 100 percent by weight of a coalesced block copolymer latex of poly(vinyl alcohol) with polyvinyl(benzyl ammonium chloride), and 0 to 95 percent by weight of a water soluble polymer selected from the group consisting of poly(vinyl alcohol), poly(vinyl pyrrolidone), and copolymers thereof. In the '405 patent there is also disclosed an ink jet recording sheet comprising a layer which includes poly(vinyl pyrrolidone). A support is also disclosed in the '405 patent, which support may include polycarbonates, see column 4, line 62, for example. The disclosures of each of the aforementioned patents are totally incorporated herein by reference.
In U.S. Pat. No. 4,680,235 there is disclosed an ink jet recording material with image stabilizing agents, see column 4, lines 32 to 58, for example. Also, in column 4, line 57, for example, this patent discloses the use of a plasticizer in a surface recording layer.
In addition to the aforesaid '405 and '235 patents there were located as a result of a patentability search U.S. Pat. No. 4,555,437, which discloses an ink jet transparency with a sulfurous acid salt component which enhances the image bleed resistance of the transparency, reference for example column 3, lines 1 to 9; and 4,578,285, which discloses a water based transparency coating typically comprised of polyurethane and a polymer such as polyvinylpyrrolidone, PVP/vinyl acetate copolymer, polyethylene oxide, gelatin, or polyacrylic acid.
Further, in U.S. Pat. No. 4,701,837 there is disclosed a light transmissive medium having a crosslinked-polymer ink receiving layer; and U.S. Pat. No. 4,775,594 describes an ink jet transparency with improved wetting properties.
Other coatings for ink jet transparencies include blends of carboxylated polymers with poly(alkylene glycol), reference U.S. Pat. No. 4,474,850; blends of poly(vinyl pyrrolidone) with matrix forming polymers such as gelatin; or poly(vinyl alcohol), swellable by water and insoluble at room temperature but soluble at elevated temperatures, reference U.S. Pat. No. 4,503,111; and blends of poly(ethylene oxide) with carboxymethyl cellulose as illustrated in U.S. Pat. No. 4,592,954, mentioned herein, the disclosure of each of the aforementioned patents being totally incorporated herein by reference.
Further, in U.S. Pat. No. 4,592,954, mentioned herein, the disclosure of which is totally incorporated herein by reference, there is illustrated a transparency for ink jet printing comprised of a supporting substrate and thereover a coating consisting essentially of a blend of carboxymethyl cellulose, and polyethylene oxides. Also, in this patent there is illustrated a transparency wherein the coating is comprised of a blend of hydroxy propyl methyl cellulose and poly(ethylene glycol monomethyl ether), a blend of carboxy methyl cellulose and poly(vinyl alcohol), or a blend of hydroxyethyl cellulose and vinyl pyrrolidone/diethylamino methylmethacrylate copolymer. One disadvantage associated with the transparencies of U.S. Pat. No. 4,592,954 is their insufficient resistance to relative humidities of, for example, exceeding 50 percent at 80.degree. F. which leads to the onset of blooming and bleeding of colors in the printed text or graphics only in four to six hours. These and other disadvantages are avoided with the transparencies of the present invention.
In U.S. Pat. No. 4,865,914, the disclosure of which is totally incorporated herein by reference, there are illustrated ink jet transparencies and ink jet papers with coatings thereover which are compatible with the inks selected for marking, and wherein the coatings enable acceptable optical density images to be obtained. More specifically, in one embodiment of the aforesaid application there are provided ink jet transparencies comprised of a supporting substrate, and a coating thereover comprised of a ternary mixture of hydroxypropyl cellulose, carboxymethyl cellulose, and poly(ethylene oxide). Moreover, in another embodiment disclosed in the patent there are provided coatings for ink jet paper comprised of a supporting substrate, and thereover a quaternary mixture of hydroxy propyl cellulose, carboxymethyl cellulose, poly(ethylene oxide), and colloidal silica.
A specific embodiment of U.S. Pat. No. 4,865,914 is directed to a transparency comprised of a supporting substrate, and thereover a blend comprised of poly(ethylene oxide), and carboxymethyl cellulose together with a component selected from the group consisting of (1) hydroxypropyl cellulose; (2) vinylmethyl ether/maleic acid copolymer; (3) carboxymethyl hydroxyethyl cellulose; (4) hydroxyethyl cellulose; (5) acrylamide/acrylic acid copolymer; (6) cellulose sulfate; (7) poly(2-acrylamido-2-methyl) propane sulfonic acid; (8) poly(vinyl alcohol); (9) poly(vinyl pyrrolidone); and (10) hydroxypropyl methyl cellulose. Additionally, there is illustrated in the aforesaid patent ink jet papers comprised of a supporting substrate, and thereover a blend comprised of poly(ethylene oxide), and carboxymethyl cellulose together with a component selected from the group consisting of (1) hydroxypropyl cellulose; (2) vinylmethyl ether/maleic acid copolymer; (3) carboxymethyl hydroxyethyl cellulose; (4) hydroxyethyl cellulose; (5) acrylamide/acrylic acid copolymer; (6) cellulose sulfate; (7) poly(2-acrylamido-2-methyl) propane sulfonic acid; (8) poly(vinyl alcohol); (9) poly(vinyl pyrrolidone); and (10) hydroxypropyl methyl cellulose, which coating has dispersed therein additives such as colloidal silicas in an amount of from about 35 to about 65 percent by weight.
Although the transparencies illustrated in the above prior art patents are suitable for their intended purposes, there remains a need for other transparencies with new coatings thereover that are useful in ink jet printing processes, and that will enable the formulation of images with high optical densities. Additionally, there is a need for transparencies with a blend of coatings thereover that are compatible with ink jet compositions, particularly those derivable from ethylene glycol/water components, which coatings contain therein plasticizers. There is also a need for coated papers that are useful in electrostatographic imaging processes wherein images with excellent resolution and no background deposits are obtained. Another need of the present invention resides in providing transparencies with a blend of coatings that do not block (stick) at, for example, 80 percent relative humidity and at a temperature of 80.degree. F.